All tubular and pipe devices which are, by any means, mechanically or hydraulically formed to a pre-determined configuration, have been long known, through the principles of physics, to react to an opposite and secondary configuration when subjected to an internally applied static or dynamic pressure of sufficient intensity.
A principle example of the above-stated fact is the well-known metallic bellows. Making reference to the metallic bellows arrangement 10 shown in FIG. 1, there is provided therein a plurality of annually formed corrugations 12. The corrugations are formed by simultaneous and concurrent outward bulging and compression of the tube from which they are formed. The established forming techniques produce the bellows 10 shown in FIG. 1.
The right-hand end of bellows 10 of FIG. 1 is shown being sealed at 14 and the left-hand end is provided with the bellows 14 having a pressure inlet opening 14a.
By application of internal pressure through the pressure inlet 16a the original configuration of the corrugations 12 are altered to an opposite or secondary configuration as shown in FIG. 2.
More specifically, the original length L of the bellows 10 shown in FIG. 1 is forcibly extended to a predictable length, such as L1, L2 or L3 as shown in FIG. 2, which length is dependent upon the intensity of internal pressure applied as well as the inherent characteristics of the bellows which include, to name a few, the nature of the material, ductility, hardness, thickness, tube diameter, effective area and number of corrugations. All tests show confirmation of the action of the bellows to all principles of physics.
When applied in a piping system, such bellows constitute the major component of industrial expansion joints. In such piping systems it is commonly necessary to limit the allowable compression and tensile defections of the bellows by external means such as anchors provided at the pipe terminals and directional changes, or by means of external tie-rods, hinges, gimbals and the like, which are provided across the length of the bellows.
The above principles of physics are directed to annually formed corrugations of a bellows, which corrugations each lie in a plane substantially perpendicular to the longitudinal axis of the integral tube or pipe, as shown in FIGS. 1 and 2.
It is desirable to use the above technology to provide a swivel joint. Conventional commercially--marketed swivel joints, which are typically of the packed type, may be manually rotated in smaller sizes, but, due to frictional resistance within their packing gland, larger sizes require motorized and/or gear assistance for activation. It is thus desirable to provide a pressure-activated pipe swivel joint of the packless type which eliminates the need for a motor drive.